<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>ProMRDS Chapter 3 - Decentralized System Services</title>
<meta http-equiv="content-type" content="text/html; charset=iso-8859-1" />
<meta name="author" content="Trevor Taylor, Software Technology" />
<meta name="keywords" content="Microsoft Robotics Developer Studio, MRDS, DSS, Decentralized System Services" />
<meta name="description" content="Chapter 3 for the ProMRDS book." />
<link href="../Styles/Standard.css" rel="stylesheet" type="text/css" />
</head>
<body>
<img src="Images/DSS_Icon.gif" alt="DSS" align="right" style="margin:0; padding:0;" />
<table width="80%">
<tr>
<td width="200"><a href="http://www.ProMRDS.com"><img src="../Images/HomeIcon.gif" alt="ProMRDS Home Page" border="0" /></a></td>
<td width="*" align="center"><img src="Images/Chapter3.gif" alt="Chapter 3" /></td>
<td width=""></td>
</tr>
<tr>
<td colspan="3"><hr /></td>
</tr>
</table>

<div class="page">
<p class="heading"><span class="smallhead">Professional</span><br />&nbsp;&nbsp;&nbsp;Microsoft Robotics Developer Studio<br />
<a href="http://www.ProMRDS.com" onmouseout="Home.src='../Images/Home.gif';" onmouseover="Home.src='../Images/Home_f2.gif';"><img name="Home" src="../Images/Home.gif" width="150" height="25" border="0" alt="Home Page" /></a>
<a href="../ReadMe.htm" onmouseout="Contents.src='../Images/Contents.gif';" onmouseover="Contents.src='../Images/Contents_f2.gif';"><img name="Contents" src="../Images/Contents.gif" width="150" height="25" border="0" alt="Book Contents" /></a>
<a href="../Chapter2/ReadMe.htm" onmouseout="Prev.src='../Images/Previous.gif';" onmouseover="Prev.src='../Images/Previous_f2.gif';"><img name="Prev" src="../Images/Previous.gif" width="150" height="25" border="0" alt="Previous Chapter" /></a>
<a href="../Chapter4/ReadMe.htm" onmouseout="Next.src='../Images/Next.gif';" onmouseover="Next.src='../Images/Next_f2.gif';"><img name="Next" src="../Images/Next.gif" width="150" height="25" border="0" alt="Next Chapter" /></a><br />
</p>

<h1>Chapter 3 - Decentralized System Services</h1>

<h2>Summary</h2>
<p>
This chapter discusses Decentralized Software Services (DSS) using an example
with two services that communicate with each other. It demonstrates the basics
of writing services under MRDS.
</p>
<p>
DSS provides the runtime environment that allows services to
exchange messages regardless of where they are located on the
network. It uses the CCR internally. If you want
to learn MRDS, then you need to become very familiar with DSS.
</p>
<p>
A simplified view of services running under DSS is shown below:
</p>
<img src="Images/DSS.gif" width="475" height="300" alt="DSS Architecture" />

<h2>Contents</h2>
<p>
The following application is included in this Chapter:<br />
ServiceA and ServiceB
</p>
<p>
In the screenshot below you can see that Service A is periodically
retrieving simulated sensor information from Service B.
</p>
<img src="Images/ServiceA_and_B.JPG" alt="Service A talking to Service B" />

<h2>Legal Stuff</h2>
<p>
This code is available free of charge for non-commercial use.
Please see the <a href="../Licence.htm">Licence Agreement</a>.
</p>

</div>

<hr />
<div class="footer">
Page maintained by:
<a href="m&#97;&#105;&#108;t&#111;:webmaster&#64;promrds&#46;com">webmaster&#64;promrds.com</a><br />
Last Updated: Mar-2008
</div>

</body>
</html>
